Prevalence and Characteristics of Quinolone Resistance in Isolated from Retail Foods in Lanzhou, China.

The aim of this study was to determinate the prevalence of in retail foods and its resistance to quinolones in retail foods in Lanzhou, People's Republic of China. In this work, 2,182 food samples, collected from March 2015 to December 2018, were analyzed to detect and then analyzed for serotype distribution, quinolone resistance, and quinolone-resistant gene detection. The findings demonstrate that the overall prevalence of in these food categories was low. A total of 41 (1.9%) of 2,182 food samples were found to be positive for . Ten distinct serovars were identified, and Derby, Anatum, and Enteritidis were the most prevalent serovars. According to the broth microdilution test, the resistance percentages were 90.2% to nalidixic acid, 39.0% to enrofloxacin, 41.5% to ciprofloxacin, 29.3% to ofloxacin, and 26.8% to levofloxacin. Among the quinolone-resistant isolates, 12 strains had a single mutation in at codon 83 (Ser→Phe) or codon 87 (Asp→Asn or Asp→Gly). Five isolates had one mutation (Ser80→Arg) and one or two hot spot mutations. genes were found in seven isolates (five and two ), and the gene in seven isolates. Two isolates carry both and genes. Based on these results, a low prevalence of contamination in retail foods was found, but it might play a potential risk factor in the spread of quinolone-resistant strains in the Lanzhou region.